Accession Number : AD0877012

Title :   Magnetic and Dielectric Loss in Magnetic Insulators.

Descriptive Note : Final technical rept. Jul 67-Jul 69,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE CENTER FOR MATERIALS SCIENCE AND ENGINEE RING

Personal Author(s) : Epstein, David J.

Report Date : AUG 1970

Pagination or Media Count : 142

Abstract : Magnetic loss and electrical transport have been studied in a series of single crystals of Y3Si(x)Fe(5-x)O(12), 0<x<0.1 (Si-YIG). Single crystal 'picture-frame' samples were prepared for studies of domain-wall dynamics. Measurements of initial permeability, made over a temperature range 4 - 300K, reveal a temperature activated wall-damping identified with the valence-exchange loss process. Microwave resonance experiments over the range 300 - 550K reveal an anomalous loss peak identified with a four-level valence-exchange model. Evidence obtained from measurements of dc conductivity and Hall effect, over the temperature range 300 - 1000K, suggests that conduction in Si-YIG occurs via band conduction and not by electron hopping as previously believed. Crystals were grown both by the conventional flux procedure and by a new top-seeded solution method. (Author)

Descriptors :   (*GARNET, MAGNETIC PROPERTIES), (*SINGLE CRYSTALS, CRYSTAL GROWTH), (*RADAR SIGNALS, ABSORPTION), MAGNETIC RESONANCE, ELECTRICAL CONDUCTIVITY, HALL EFFECT, YTTRIUM COMPOUNDS, IRON COMPOUNDS, SILICON, DOPING, ANOMALIES.

Subject Categories : Active & Passive Radar Detection & Equipment
      Crystallography
      Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE